Efficiency droop improvement for InGaN-based light-emitting diodes with gradually increased In-composition across the active region

The gradually increased In-composition barriers were proposed to synthesize advantages of low polarization of InGaN barriers and high barrier height of GaN barriers. The reference structure with GaN barriers, the structure A with constant In-composition InGaN barriers and the structure B with gradually increased In-composition InxGa1−xN barriers were chosen. The light-emitting diodes were numerically studied. It is found that the structure B has the best performance. The output power is increased by 28% for structure B compared with structure A at 180 mA. The improved performance is caused by the enhanced electron confinement and increased hole injection efficiency.